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Question
The mean of 100 observations is 40 and their standard deviation is 3. The sum of squares of all deviations is
Options
40000
160900
160000
30000
Solution
160900
Explanation;
Hint:
σ = 3
`(sumx^2)/"n" - ((sumx)/"n")^2` = 9
`(sumx^2)/100 - 40^2` = 9
`(sumx^2)/100` = 9 + 1600
`(sumx^2)/100` = 1609
`sumx^2` = 160900
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